Cal Fire/Riverside County Firefighters perform a helicopter water rescue as they hoist Jose Vicente, a homeless man, from the Santa Ana River Bottom after his encampment was flooded by heavy rain near the 2300 block of Fleetwood Drive in Jurupa Valley on Thursday, February 14, 2019. (Photo by Terry Pierson, The Press-Enterprise/SCNG)

Along with the web of freeways and busy interchanges, Southern California’s cities are also tied together by a vast network of rivers, creeks and flood canals.

Most of the time, much of this network is bone dry, forming pencil-thin lines along the regional map. Though when heavy rains begin to fall, as they did Thursday in nearly record-breaking levels, the waterways can quickly swell into bulging limbs, grabbing people, vehicles, homes, debris — anything within their reach. In at least two cases Thursday, the flood waters claimed the lives of two people: a man in the rural Riverside County community of Sage and a 20 year old woman who was swept from Riverside into Corona along a flood canal.

Just a dozen days earlier, an elderly man was killed in Yucca Valley in San Bernardino County when the vehicle he was in was overcome by rushing waters in a wash from a storm on Feb. 2. Two others managed to escape the overturned vehicle.

For the fire and law enforcement agencies responsible for dropping a lifeline to the residents who come in contact with the region’s potentially lethal waterways, Thursday was especially busy and dangerous. In all, rescue crews in Riverside, San Bernardino and Los Angeles counties pulled at least 50 people from the raging flood waters.

“For us, this might be the most we’ve had in a day for water rescues, maybe in the last 10 years — maybe period,” said Capt. Frank Abril with the Riverside County Fire Department and Cal Fire. He led a helicopter crew that rescued six people from swift water scenarios Thursday.

His crew faced obstacles that added risk to the operations. Low-hanging clouds limited visibility, the helicopter risked being caught in nearby trees and debris kicked up from homeless encampments could have jammed the rotor system.

Though for Abril, who has served as captain of his crew for the past decade, he said he no longer gets nervous or anxious before operations.

In short, the routine looks like this: Officials get a call about a rescue. A pilot starts the engine of the military-grade helicopter, a UH-1H, which sits at a Hemet airport. Six other crew members drape gear over their bodies — dry suits, harnesses, white helmets, radios, flotation devices and egress bottles that provide oxygen in case the helicopter crashes into the water. This takes about four minutes. Each crew member is wearing ear protection, but they can still hear the turbine engine whining as it starts up. They hop into the helicopter that weighs well over two tons. The aircraft rises and flies at about 120 miles per hour. The crew locates the patient. Once a plan is coordinated, the crew will typically use a cable system to hoist the patient into the helicopter, fastening them with a seat belt. They fly back to Hemet. The patient is evaluated by paramedics, sometimes transported to a hospital. The crew debriefs. They clean and inspect their gear. The helicopter is refueled. The crew waits for the next call.

Abril and his crew repeated this routine three times Thursday.

Rescue crews pulled dozens off people out of the Santa Ana River in San Bernardino and Riverside county during a rain storm on Feb. 14, 2019. (Photo via Twitter)

The day began in Cabazon, a desert community off the 10 Freeway in northeast Riverside County, where a man and woman drove their car into a flooded road. Underestimating the rising current, the car was shoved off the road and into the water. The pair called 9-1-1, stood on the roof of their car and awaited rescue. Abril said the water, which moved at about 25 miles per hour, tipped the car to its side, knocking the pair into the water. They were swept over to a nearby sandbar, while the water hauled their car downstream. After a 16-minute flight from Hemet, Abril and his crew landed on the sandbar and scooped the man and woman into the aircraft.

West of Cabazon, the Santa Ana River, which snakes through Riverside and San Bernardino counties, held dozens captive among its torrential grip.

The Santa Ana River is where Abril’s crew closed its day. In Jurupa Valley where the riverbed widens, his crew rescued a man who stood atop a makeshift shelter as water surged around him.

A rescued woman reacts as she is pulled across the rain-swollen Santa Ana River by a San Bernardino County Fire Department swift water rescue team Thursday, February 14, 2019. (Photo by Will Lester, Inland Valley Daily Bulletin/SCNG)

In San Bernardino County, helicopter crews with the San Bernardino County Sheriff’s Department rescued 15 people who were trapped among the Santa Ana’s angry flow.

In Riverside, a 20-year-old transient named Stacie Mills-Nichols and her boyfriend were dragged into the concrete flood canal that they had called home. The two tried to hold on to a wooden pallet. Somewhere along the canal, as the water whisked them past homes, businesses, and freeways, Mills-Nichols let go. Nearly 10 miles downstream from her encampment, Corona rescue crews found her unconscious body in a muddy runoff that flows directly into the Santa Ana River. She was pronounced dead at a local hospital Thursday morning.

CAL FIRE/Riverside County Firefighters, performed a helicopter water rescue as they hoist Jose Vicente a homeless man from the Santa Ana River Bottom after his encampment was flooded by heavy rain near the 2300 block of Fleetwood Drive in Jurupa Valley on Thursday, February 14, 2019. (Photo by Terry Pierson, The Press-Enterprise/SCNG)

By the afternoon, emergency alerts went out to people’s cell phones across both counties: “Santa Ana River unsafe-GET OUT NOW. Stay away from river and waterways leading to river.”

The 96-mile-long river also cuts through Orange County, mostly in the form of a concrete canal, before emptying into the ocean.

Orange County Fire Authority Capt. Tony Bommarito said fire crews are trained to rescue people who may fall into the river. He said county fire crews were not called to any swift water rescues in the past year. “It is rare, but you see it,” he said.

In Los Angeles County, the Los Angeles and San Gabriel rivers pose similar risks to residents. On Thursday, crews with the Los Angeles County Fire Department used a raft to rescue three people who were stuck in a tree surrounded by water flowing from the San Gabriel River.

Jason Robertson, battalion chief of the department’s public information office, said that every county firefighter is trained to conduct shore-based water rescues. In trickier situations, tactical units use rafts, Jet Skis, or helicopters, as was the case during a January storm when fire crews hoisted a man living along the San Gabriel River in the City of Industry who awoke to storm waters rising quickly around him.

Robertson said law enforcement agencies are tasked with alerting people who live inside the riverbeds, warning them of oncoming storms. Such is the case in Corona, where police use their HOPE team to reach the many homeless people who sleep in or near rivers and canals.

Corona is a meeting point for many flood canals in the region, said Capt. Ryan Rolston, spokesman for the city’s fire department. The high volume of flood canals may spell an increase in risk for both victims who get caught in storm waters and the crews who rescue them. On Thursday, Corona crews rescued nine people. Most were living in riverbed encampments. Among them was Mills-Nichols and her boyfriend, who also lived together in a Riverside canal.

Rolston said fire crews train for these operations year-round, but Thursday’s storm brought the highest volume of rescues he has seen since starting at the department in 2004.

From his time there, Rolston could not recall another death during a swift water event. He said in the event of a fatality, counselors and psychologists are made available to the fire crews. But sometimes, talking things out among each other may be the best way to deal with potentially traumatic situations, Rolston said. Thursday’s deadly storm was no exception.

“We’re such a close-knit family, and we all worked with each other for a long time,” he said. “We all speak to each other openly. That’s usually the best way.”